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Brain ageing, the primary risk factor for cognitive impairment, occurs because of the accumulation of age-related neuropathologies. Identifying effective nutrients that increase cognitive function may help maintain brain health. Tomatoes and lemons have various bioactive functions and exert protective effects against oxidative stress, ageing and cancer. Moreover, they have been shown to enhance cognitive function. In the present study, we aimed to investigate the effects of tomato and lemon ethanolic extracts (TEE and LEE, respectively) and their possible synergistic effects on the enhancement of cognitive function and neurogenesis in aged mice. The molecular mechanisms underlying the synergistic effect of TEE and LEE were investigated. For the in vivo experiment, TEE, LEE or their mixture was orally administered to 12-month-old mice for 9 weeks. A single administration of either TEE or LEE improved cognitive function and neurogenesis in aged mice to some extent, as determined using the novel object recognition test and doublecortin immunohistochemical staining, respectively. However, a significant enhancement of cognitive function and neurogenesis in aged mice was observed after the administration of the TEE + LEE mixture, which had a synergistic effect. N-methyl-d-aspartate receptor 2B, postsynaptic density protein 95, and brain-derived neurotrophic factor (BDNF) levels and tropomyosin receptor kinase B (TrkB)/extracellular signal-regulated kinase (ERK) phosphorylation also synergistically increased after the administration of the mixture compared with those in the individual treatments. In conclusion, compared with their separate treatments, treatment with the TEE + LEE mixture synergistically improved the cognitive function, neurogenesis and synaptic plasticity in aged mice via the BDNF/TrkB/ERK signalling pathway.
Mood disorders require consistent management of symptoms to prevent recurrences of mood episodes. Circadian rhythm (CR) disruption is a key symptom of mood disorders to be proactively managed to prevent mood episode recurrences. This study aims to predict impending mood episodes recurrences using digital phenotypes related to CR obtained from wearable devices and smartphones.
Methods
The study is a multicenter, nationwide, prospective, observational study with major depressive disorder, bipolar disorder I, and bipolar II disorder. A total of 495 patients were recruited from eight hospitals in South Korea. Patients were followed up for an average of 279.7 days (a total sample of 75 506 days) with wearable devices and smartphones and with clinical interviews conducted every 3 months. Algorithms predicting impending mood episodes were developed with machine learning. Algorithm-predicted mood episodes were then compared to those identified through face-to-face clinical interviews incorporating ecological momentary assessments of daily mood and energy.
Results
Two hundred seventy mood episodes recurred in 135 subjects during the follow-up period. The prediction accuracies for impending major depressive episodes, manic episodes, and hypomanic episodes for the next 3 days were 90.1, 92.6, and 93.0%, with the area under the curve values of 0.937, 0.957, and 0.963, respectively.
Conclusions
We predicted the onset of mood episode recurrences exclusively using digital phenotypes. Specifically, phenotypes indicating CR misalignment contributed the most to the prediction of episodes recurrences. Our findings suggest that monitoring of CR using digital devices can be useful in preventing and treating mood disorders.
There are growing concerns about the impact of the COVID-19 pandemic on the mental health of older adults. We examined the effect of the pandemic on the risk of depression in older adults.
Methods
We analyzed data from the prospective cohort study of Korean older adults, which has been followed every 2 years. Among the 2308 participants who completed both the third and the fourth follow-up assessments, 58.4% completed their fourth follow-up before the outbreak of COVID-19 and the rest completed it during the pandemic. We conducted face-to-face diagnostic interviews using Mini International Neuropsychiatric Interview and used Geriatric Depression Scale. We performed generalized estimating equations and logistic regression analyses.
Results
The COVID-19 pandemic was associated with increased depressive symptoms in older adults [b (standard error) = 0.42 (0.20), p = 0.040] and a doubling of the risk for incident depressive disorder even in euthymic older adults without a history of depression (odds ratio = 2.44, 95% confidence interval 1.18–5.02, p = 0.016). Less social activities, which was associated with the risk of depressive disorder before the pandemic, was not associated with the risk of depressive disorder during the pandemic. However, less family gatherings, which was not associated with the risk of depressive disorder before the pandemic, was associated with the doubled risk of depressive disorder during the pandemic.
Conclusions
The COVID-19 pandemic significantly influences the risk of late-life depression in the community. Older adults with a lack of family gatherings may be particularly vulnerable.
Oxidative stress causes several diseases and dysfunctions in cells, including oocytes. Clearly, oxidative stress influences oocyte quality during in vitro maturation and fertilization. Here we tested the ability of coenzyme Q10 (CoQ10) to reduce reactive oxygen species (ROS) and improve mouse oocyte quality during in vitro culture. Treatment with 50 μM CoQ10 efficiently reduced ROS levels in oocytes cultured in vitro. The fertilizable form of an oocyte usually contains a cortical granule-free domain (CGFD). CoQ10 enhanced the ratio of CGFD–oocytes from 35% to 45%. However, the hardening of the zona pellucida in oocytes was not affected by CoQ10 treatment. The in vitro maturation capacity of oocytes, which was determined by the first polar body extrusion, was enhanced from 48.9% to 75.7% by the addition of CoQ10 to the culture medium. During the parthenogenesis process, the number of two-cell embryos was increased by CoQ10 from 43.5% to 67.3%. Additionally, treatment with CoQ10 increased the expression of Bcl2 and Sirt1 in cumulus cells. These results suggested that CoQ10 had a positive effect on ROS reduction, maturation rate and two-cell embryo formation in mouse oocyte culture.
Building on prior research on management fashion, this paper seeks to understand how management consultants respond to the boom-to-bust cycles of competing management fashion trends. Specifically, we examine how US management consulting firms offering total quality management (TQM) services responded to the rise and fall of the rival management practice, business process reengineering (BPR), with an empirical focus on the adoption of BPR services. We find that a consulting firm offering TQM services was more likely to adopt BPR services if the firm’s organizational capabilities and institutional environments were more connected to BPR’s principles than to TQM’s principles. This suggests that management fashions are not simply bandwagon phenomena, but involve resource- and identity-based decision making. We also find that the significance of organizational capabilities increased while that of network influences decreased as BPR’s boom turned to bust. The reversal of well-established institutional accounts of innovation diffusion is explained by reference to the characteristics of management fashion.
We aimed to evaluate the reproducibility and validity of the newly developed FFQ for the Korean National Health and Nutrition Examination Survey (KNHANES) and to estimate the measure’s calibration factors.
Design
The 109-item FFQ was administered twice, approximately 9 months apart. We also collected four seasonal 3 d dietary records (DR) as a reference method. Correlation coefficients and joint classification were computed to compare intakes of energy, thirteen nutrients and eleven food groups between the two FFQ to evaluate reproducibility. For validity, de-attenuated and energy-adjusted correlation, joint classification and Bland–Altman statistics were calculated for energy and nutrients between the first FFQ and the DR. To calibrate the FFQ, we performed a linear regression analysis in which the DR were the dependent variables and FFQ, age and sex were the independent variables.
Setting
Seoul metropolitan area, Republic of Korea.
Subjects
A total of 126 adults aged 20–65 years.
Results
The average correlation coefficients measuring reproducibility were 0·54 for nutrients and 0·57 for food groups. The mean correlation coefficient measuring validity was 0·40 for all nutrients between the first FFQ and the DR. On average, 75 % of the participants were classified into the same or adjacent quartiles, while 5 % of the participants were grossly misclassified. The mean energy and nutrient intakes estimated by the calibrated FFQ were similar to the means estimated by the DR.
Conclusions
The newly developed FFQ for assessing dietary intake in the KNHANES has acceptable reproducibility and modest validity compared with a 12 d DR collected over a 9-month period.
Sources of variation in nutrient intake have been examined for Western diets, but little is known about the sources of variation and their differences by age and sex among Koreans. We examined sources of variation in nutrient intake and calculated the number of days needed to estimate usual intake using 12 d of dietary records (DR). To this end, four 3 d DR including two weekdays and one weekend day were collected throughout four seasons of 1 year from 178 male and 236 female adults aged 20–65 years residing in Seoul, Korea. The sources of variation were estimated using the random-effects model, and the variation ratio (within-individual:between-individual) was calculated to determine a desirable number of days. Variations attributable to the day of the week, recording sequence and seasonality were generally small, although the degree of variation differed by sex and age (20–45 years and 46–65 years). The correlation coefficient between the true intake and the observed intake (r) increased with additional DR days, reaching 0·7 at 3–4 d and 0·8 at 6–7 d. However, the degree of increase became attenuated with additional days: r increased by 13·0–26·9 % from 2 to 4 d, by 6·5–16·4 % from 4 to 7 d and by 4·0–11·6 % from 7 to 12 d for energy and fifteen nutrients. In conclusion, the present study suggests that the day of the week, recording sequence and seasonality minimally contribute to the variation in nutrient intake. To measure Korean usual dietary intake using open-ended dietary instruments, 3–4 d may be needed to achieve modest precision (r>0·7) and 6–7 d for high precision (r>0·8).
We present experimental evidence of enhancement of thermoelectric properties in tellurium (Te) nanoparticle-embedded bismuth antimony telluride (BiSbTe) alloys. Bi0.5Sb1.5Te3 films with a high density of Te particles of 10–20 nm size were prepared by growth of alternating multilayers of ultrathin Te and Bi0.5Sb1.5Te3. As the amount of Te nanoinclusions increased up to ∼15%, the Seebeck coefficient and thermoelectric power factor were increased. Based on the concept of band bending at heterointerfaces as a carrier energy filter, the energy relaxation calculation was made to confirm that the Te nanoinclusions result in a carrier energy filtering effect in p-type bismuth antimony telluride. In addition, thermal conductivities were reduced in the Te-embedded samples, permitting possible further enhancement of the thermoelectric figure of merit. The advantages of Te nanoinclusions in p-type Bi0.5Sb1.5Te3alloys on thermoelectric performance are experimentally realized by both electron- and phonon scattering.
Determining valid zygosity is a basic and important requirement in a twin study, because misdiagnosing zygosity leads to biased results. The Healthy Twin Study has collected data from adult like-sex twins and their families since 2005. In the study, a questionnaire to determine zygosity was developed comprising four questions; one concerning the degree of resemblance, and three concerning the degree of confusion by the resemblance. Among 2,761 individuals (624 twin pairs) of twin and their families, 406 pairs of twins (mean age 38.3, 63.5% women) with both questionnaire and genotype information were selected to examine the validity of the zygosity questionnaire using 16 short tandem repeat markers. We first determined individual zygosity including undetermined category, and then decided the zygosity of a twin pair using a decision tree. Sensitivity of questionnaire diagnosis was 98.8% for monozygotic (MZ) and 88.9% for dizygotic (DZ) twins, and positive predictive value was 97.2% for MZ and 95.0% for DZ. When we compared correctly and wrongly diagnosed twin pairs, misdiagnosed DZ twins (nine pairs) showed striking similarity in stature or obesity even exceeding that of true MZ twins. Our finding suggests that a parsimonious questionnaire method of diagnosing the zygosity will be useful, and adding physical or physiological measurements to a questionnaire of zygosity diagnosis will either confound the correct diagnosis or reduce the efficiency of the study compared with using questionnaire alone or with introducing genotyping.
Two studies are reported using the theory of planned behaviour (TPB) to examine Koreans' intentions and self-reported behaviour of joining and not joining alcohol-related social gatherings with work colleagues after work hours. Study 1 showed that group-related attitudes and perceived behavioural control of the TPB components regarding joining were significantly associated with intentions to join. Study 2 examined TPB components regarding not joining and intentions to not join. Study 2 found that although none of the TPB components was directly related to intentions, subjective norms from work colleagues moderated the effect of group-related attitudes on intentions to not join. The TPB components and intentions were not significantly related to self-reported behaviour of joining. The findings indicate that the relationships between the TPB components and intentions can be different for engaging and not engaging in a behaviour.
Plant genetic resources (PGR) include cultivars, landraces, wild species closely related to cultivated varieties, breeder's elite lines and mutants. The loss of genetic diversity caused by the practice of agriculture and the availability of genetic information has resulted in a great effort dedicated to the collection of PGR. Prior to the advent of molecular profiling, accessions in germplasm collections were examined based on morphology. The development of molecular techniques now allows a more accurate analysis of large collections. Next-generation sequencing (NGS) with de novo assembly and resequencing has already provided a substantial amount of information, which warrants the coordination of existing databases and their integration into genebanks. Thus, the integration and coordination of genomic data into genebanks is very important and requires an international effort. From the determination of phenotypic traits to the application of NGS to whole genomes, every aspect of genomics will have a great impact not only on PGR conservation, but also on plant breeding programmes.
We investigated the pressure dependence of the inductive coupled plasma (ICP) oxidation on the electrical characteristics of the thin oxide films. Activation energies and electron temperatures with different pressures were estimated. To demonstrate the pressure effect on the plasma oxide quality, simple N type metal-oxide-semiconductor (NMOS) transistors were fabricated and investigated in a few electrical properties. At higher pressure than 200mTorr, plasma oxide has a slightly higher on-current and a lower interfacial trap density. The on-current gain seems to be related to the field mobility increase and the lower defective interface to the electron temperature during oxidation.
To investigate the annual rate of tuberculosis (TB) infection among newly employed nurses using both tuberculin skin test (TST) and QuantiFERON-TB Gold (QFT-G; Cellestis Limited) assay.
Design.
A prospective cohort study involving newly employed nurses.
Setting.
A tertiary care university hospital in South Korea.
Methods.
All participants (n = 196) were tested with the TST and QFT-G assay at baseline. After 1 year, the TST and QFT-G assay were reperformed for subjects who had negative TST results at baseline and for all subjects, respectively.
Results.
The baseline TST and QFT-G assays were positive for 101 subjects (51.5%) and 28 subjects (14.3%), respectively; 22 subjects (11.2%) had positive results of both tests. Although the overall between-test agreement was 54.9% (κ = 0.151 [95% confidence interval, 0.047–0.245]), agreement improved to 78.5% (κ = 0.462 [95% confidence interval, 0.007–0.917]) for subjects who had not received bacille Calmette-Guérin vaccination. After 1 year, the TST yielded positive results for 16 (21.3%) of 75 nurses with negative baseline results, and the QFT-G assay yielded positive results for 21 (14.4%) of 146 subjects with negative baseline Results. Collectively, 5 subjects (3.0%) experienced conversion to positive results with both tests, and 32 subjects (18.9%) experienced conversion to positive results with one of the tests. Neither the employing hospital department nor exposure to patients with TB affected test conversion status.
Conclusions.
The poor overall agreement between TST and QFT-G results may have been caused by the confounding effect of bacille Calmette-Guérin vaccination. The annual risk of TB infection among newly employed nurses was at least 3% on the basis of results of both the TST and QFT-G test. Stricter preventive strategies against TB spread should be implemented in our hospital.
For a robotic workcell with multiple robots, several interconnection methods are presented in terms of a processor-based architecture. The concept of the multiple processor system (MPS) or multiple computer system (MCS) is used to formulate and analyze the multi-robot interconnection system (MRIS). The MRIS is modelled as a queueing network, and mathematical analysis is done on the basis of modelling. Performance evaluation is achieved for the MRIS through the mean value analysis with the response time and the probability of service failure under different workloads. The results together with some comments suggest a useful guideline for a selecting an appropriate interconnection method for the MRIS subject to the system environment and application.
The prevalence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains causing bloodstream infection (BSI) has not been studied in Korea.
Objective.
We sought to determine the prevalence of CA-MRSA strains among isolates recovered from patients with MRSA BSIs and to explore epidemiological changes in Korea. We also sought to evaluate clinical characteristics relevant to the development of healthcare-associated BSIs.
Methods.
We prospectively collected consecutive MRSA isolates from patients with BSI at 4 hospitals from July 1 through November 30, 2007, and we also included MRSA isolates recovered from culture of blood samples collected during a previous year (October 1, 2004 through September 30, 2005) at a different hospital. Molecular typing studies were performed, including pulsed-field gel electrophoresis (PFGE), multilocus sequence typing, Staphylococcus protein A (spa) typing, and staphylococcal cassette chromosome mec (SCCmec) typing. We compared the clinical characteristics and outcomes of patients with healthcare-associated BSI due to CA-MRSA strains with those of patients with healthcare-associated BSI due to healthcare-associated MRSA (HA-MRSA) strains.
Results.
There were 76 cases of MRSA BSI, of which 4 (5.3%) were community-associated and 72 (94.7%) were healthcare-associated. Among the 72 HA-MRSA BSIs, 18 (25%) were community onset, and 54 (75%) were hospital onset. PFGE type D-ST72–spa B-SCCmec type IVA MRSA, the predominant genotype of CA-MRSA in Korea, accounted for 19 (25%) of all 76 MRSA BSIs, including 17 (23.6%) of 72 HA-MRSA BSIs and 11 (20.8%) of 53 hospital-onset HA-MRSA BSIs. Patients with healthcare-associated BSIs due to CA-MRSA strains carrying SCCmec type IVA tended to have fewer healthcare-associated risk factors, compared with patients with healthcare-associated BSIs due to HA-MRSA strains carrying other SCCmec types. The presence of a central venous catheter or other invasive device was the only independent factor differentiating patients infected with hospital-associated genotype strains from patients infected with other strains. Clinical outcomes were similar between both groups.
Conclusions.
CA-MRSA strains are emerging as a major cause of BSI in healthcare settings in Korea. This changing epidemiology of MRSA poses a challenge to public health and infection control in hospital settings.
A nonvolatile memory device with the multi-layered SiC nanocrystals embedded in the SiO2 dielectrics for long-term data storage was fabricated and its electrical properties were evaluated. The SiC nanocrystals were formed by using post thermal annealing process. The transmission electron microscope analysis showed the multi-layered SiC nanocrystals between the tunnel and the control oxide layers. The average size and density of the SiC nanocrystals were approximately 5 nm and 2×1012 cm-2, respectively. The memory window of nonvolatile memory devices with the multi-layered of SiC nanocrystals was about 2.7 V during the operations at ±10 V for 700 ms, and then it was maintained around at 1.1 V after 105 sec.
The aim of this study was to investigate the usefulness of a three-dimensional (3D) reconstruction of computed tomography (CT) images in determining the anatomy and topographic relationship between various important structures. Using 40 ears from 20 patients with various otological diseases, a 3D reconstruction based on the image data from spiral high-resolution CT was performed by segmentation, volume-rendering and surface-rendering algorithms on a personal computer. The 3D display of the middle and inner ear structures was demonstrated in detail. Computer-assisted measurements, many of which could not be easily measured in vivo, of the reconstructed structures provided accurate anatomic details that improved the surgeon’s understanding of spatial relationships. A 3D reconstruction of temporal bone CT might be useful for education and increasing understanding of the anatomical structures of the temporal bone. However, it will be necessary to confirm the correlation between the 3D reconstructed images and histological sections through a validation study.
Porcelain (veneer layer)/alumina (core layer) is a typical dental crown structure. Due to its high incidence of failure, a new porcelain/mullite (buffer layer)/alumina trilayer structure is designed, fabricated, and evaluated. Alumina green bodies were prepared by gel-casting process, and then calcined at 900 and 1100°C to infiltrate mullite precursor slurry of silica-rich (Al2O3·2SiO2) composition into the bodies. Porosity in the bodies is not dependent on calcination temperature, resulting in a similar infiltration depth. Porcelain was coated on the alumina sintered at 1600°C with and without mullite buffer layer. There are no delamination or cracks observed after firing the layered materials. Rod type microstructure and continuous composition are indicated at the interface in the case of the layered structure with mullite buffer layer. To investigate the cracking resistance behavior for this new structure, Vickers indentation and Hertzian contact fatigue tests were conducted. Cracks do not penetrate the interface with mullite buffer layer into the porcelain, showing a reversal case for the layered structure without mullite buffer layer. The layered structure with mullite buffer layer shows higher critical load for fracture than that without mullite buffer layer. Fracture mode of the layered structures in cyclic fatigue shows a top layer (porcelain) fracture at relatively low load (P = 250 N) and higher cycles (n = 106), and a bottom layer (alumina) fracture at higher load (P = 300 N) and relatively low cycles (n = 105).
Large area, flat panel detectors are being investigated for digital radiogrpahy and fluoroscopy. Theses detectors employ an x-ray conversion layer of photoconductor to detect x-rays. The amorphous selenium layer that is currently being studied for its use as an x-ray photoconductor is not pure a-Se but rather a-Se doped with 0.2-0.5% As and 10-30 ppm Cl, also known as stabilized a-Se. The suitability of the stabilized a-Se is largely determined by its charge on generating, transporting and trapping properties.
In this paper, a conventional time-of-flight measurement was carried out to analyze the transport properties of charge carriers. A laser beam with pulse duration of 5 ns and wavelength of 350 nm was illuminated on the surface of the stabilized a-Se with thickness of 400 μm. The photo response signals of the hole and electron were measured at the applied electric field of 10 V/μm as a function of time. The measured transit times of the hole and electron were about 229.17μs and about 8.73μs at 10 V/μm, respectively. The measured mobility indicated a slight dependence with respect to the applied electric field with a range of 4-10 V/μm. The experimental results showed that the measured mobility of the hole and electron was 0.04584 cm2V-1s-1 and 0.00174 cm2V-1s-1 at the electric field of 10 V/μm.
Nowadays, large area, flat panel solid state detectors are being investigated for digital radiography. In this paper, development and evaluation of a selenium-based flat-panel digital xray detector are described. The prototype detector has a pixel pitch of 139μm and a total active imaging area of 7″×8.5″, giving a total of 1.9 million pixel. This detector include a x-ray imaging layer of amorphous selenium as a photoconductor which is evaporated in vacuum state on a TFT flat panel, to make signals in proportion to incident x-ray. The film thickness was about 500μm. To evaluate the imaging performance of the digital radiography (DR) system developed in our group, sensitivity, linearity of the response of exposure, the modulation transfer function(MTF) and detective quantum efficiency(DQE) of detector was measured. The measured sensitivity was 4.16×106 ehp/pixel mR at the bias field of 10 V/μm: The beam condition was 41.9 KeV. Measured MTF at 2.5 lp/mm was 52%, and the DQE at 1.5 lp/mm was 75%.